Following the arguments presented in Ref. [1]}, we can also express the Fermi velocity of the Dirac cone in terms of the wavefunction at \(K_m\) . For this purpose, we choose the basis \(\Phi ^{\prime } = (\phi _{t,A}, \phi _{b, A}, \phi _{t, B}, \phi _{b, B})\) , and the zero modes at \(K_m\)  satisfy the equation
\(& \begin{pmatrix}0 & \mathcal {D}(x) \\ \mathcal {D}^{\dagger }(x) & 0\end{pmatrix} \begin{pmatrix}\Phi _{K_m, A}(x) \\ \Phi _{K_m, B}(x)\end{pmatrix} = 0,\) 
